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Fix fields_desc type hint to allow Packet class references #5020

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Fix fields_desc type hint to allow Packet class references #5020

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43 changes: 26 additions & 17 deletions scapy/packet.py
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Original file line number Diff line number Diff line change
Expand Up @@ -80,6 +80,12 @@
_T = TypeVar("_T", Dict[str, Any], Optional[Dict[str, Any]])


def _resolved_fields_desc(fields_desc):
# type: (Sequence[Union[AnyField, Type['Packet']]]) -> List[AnyField]
"""Return fields_desc entries after Packet_metaclass resolution."""
return cast(List[AnyField], list(fields_desc))


class Packet(
BasePacket,
_CanvasDumpExtended,
Expand All @@ -106,7 +112,7 @@ class Packet(
"process_information"
]
name = None
fields_desc = [] # type: ClassVar[List[AnyField]]
fields_desc = [] # type: ClassVar[List[Union[AnyField, Type[Packet]]]] # noqa: E501
deprecated_fields = {} # type: Dict[str, Tuple[str, str]]
overload_fields = {} # type: Dict[Type[Packet], Dict[str, Any]]
payload_guess = [] # type: List[Tuple[Dict[str, Any], Type[Packet]]]
Expand Down Expand Up @@ -190,7 +196,7 @@ def __init__(self,
# We use this strange initialization so that the fields
# are initialized in their declaration order.
# It is required to always support MultipleTypeField
for field in self.fields_desc:
for field in _resolved_fields_desc(self.fields_desc):
fname = field.name
try:
value = fields.pop(fname)
Expand Down Expand Up @@ -323,7 +329,7 @@ def init_fields(self, for_dissect_only=False):
"""

if self.class_dont_cache.get(self.__class__, False):
self.do_init_fields(self.fields_desc)
self.do_init_fields(_resolved_fields_desc(self.fields_desc))
else:
self.do_init_cached_fields(for_dissect_only=for_dissect_only)

Expand Down Expand Up @@ -354,7 +360,7 @@ def do_init_cached_fields(self, for_dissect_only=False):

# Build the fields information
if Packet.class_default_fields.get(cls_name, None) is None:
self.prepare_cached_fields(self.fields_desc)
self.prepare_cached_fields(_resolved_fields_desc(self.fields_desc))

# Use fields information from cache
default_fields = Packet.class_default_fields.get(cls_name, None)
Expand Down Expand Up @@ -398,7 +404,7 @@ def prepare_cached_fields(self, flist):
if isinstance(f, MultipleTypeField):
# Abort
self.class_dont_cache[cls_name] = True
self.do_init_fields(self.fields_desc)
self.do_init_fields(_resolved_fields_desc(self.fields_desc))
return

class_default_fields[f.name] = copy.deepcopy(f.default)
Expand Down Expand Up @@ -631,7 +637,7 @@ def __repr__(self):
# type: () -> str
s = ""
ct = conf.color_theme
for f in self.fields_desc:
for f in _resolved_fields_desc(self.fields_desc):
if isinstance(f, ConditionalField) and not f._evalcond(self):
continue
if f.name in self.fields:
Expand Down Expand Up @@ -770,7 +776,7 @@ def self_build(self):
if self.raw_packet_cache is not None:
return self.raw_packet_cache
p = b""
for f in self.fields_desc:
for f in _resolved_fields_desc(self.fields_desc):
val = self.getfieldval(f.name)
if isinstance(val, RawVal):
p += bytes(val)
Expand Down Expand Up @@ -851,7 +857,7 @@ def do_build_ps(self):
p = b""
pl = []
q = b""
for f in self.fields_desc:
for f in _resolved_fields_desc(self.fields_desc):
if isinstance(f, ConditionalField) and not f._evalcond(self):
continue
p = f.addfield(self, p, self.getfieldval(f.name))
Expand Down Expand Up @@ -1079,7 +1085,7 @@ def do_dissect(self, s):
# type: (bytes) -> bytes
_raw = s
self.raw_packet_cache_fields = {}
for f in self.fields_desc:
for f in _resolved_fields_desc(self.fields_desc):
s, fval = f.getfield(self, s)
# Skip unused ConditionalField
if isinstance(f, ConditionalField) and fval is None:
Expand Down Expand Up @@ -1291,8 +1297,8 @@ def __eq__(self, other):
# type: (Any) -> bool
if not isinstance(other, self.__class__):
return False
for f in self.fields_desc:
if f not in other.fields_desc:
for f in _resolved_fields_desc(self.fields_desc):
if f not in _resolved_fields_desc(other.fields_desc):
return False
if self.getfieldval(f.name) != other.getfieldval(f.name):
return False
Expand Down Expand Up @@ -1503,7 +1509,7 @@ def _show_or_dump(self,
ct.punct("###["),
ct.layer_name(self.name),
ct.punct("]###"))
fields = self.fields_desc.copy()
fields = _resolved_fields_desc(self.fields_desc).copy()
while fields:
f = fields.pop(0)
if isinstance(f, ConditionalField) and not f._evalcond(self):
Expand Down Expand Up @@ -1737,7 +1743,7 @@ def _do_summary(self):
ret = self.__class__.__name__ if self.show_summary else ""
if self.__class__ in conf.emph:
impf = []
for f in self.fields_desc:
for f in _resolved_fields_desc(self.fields_desc):
if f in conf.emph:
impf.append("%s=%s" % (f.name, f.i2repr(self, self.getfieldval(f.name)))) # noqa: E501
ret = "%s [%s]" % (ret, " ".join(impf))
Expand Down Expand Up @@ -1775,7 +1781,10 @@ def _command(self, json=False):
f = []
iterator: Iterator[Tuple[str, Any]]
if json:
iterator = ((x.name, self.getfieldval(x.name)) for x in self.fields_desc)
iterator = (
(x.name, self.getfieldval(x.name))
for x in _resolved_fields_desc(self.fields_desc)
)
else:
iterator = iter(self.fields.items())
for fn, fv in iterator:
Expand Down Expand Up @@ -2423,7 +2432,7 @@ def _pkt_ls(obj, # type: Union[Packet, Type[Packet]]
if not issubtype(obj, Packet) and not is_pkt:
raise ValueError
fields = []
for f in obj.fields_desc:
for f in _resolved_fields_desc(obj.fields_desc):
cur_fld = f
attrs = [] # type: List[str]
long_attrs = [] # type: List[str]
Expand Down Expand Up @@ -2581,7 +2590,7 @@ def rfc(cls, ret=False, legend=True):

# Generate packet groups
def _iterfields() -> Iterator[Tuple[str, int]]:
for f in cls.fields_desc:
for f in _resolved_fields_desc(cls.fields_desc):
# Fancy field name
fname = f.name.upper().replace("_", " ")
fsize = int(f.sz * 8)
Expand Down Expand Up @@ -2697,7 +2706,7 @@ def fuzz(p, # type: _P
while not isinstance(q, NoPayload):
new_default_fields = {}
multiple_type_fields = [] # type: List[str]
for f in q.fields_desc:
for f in _resolved_fields_desc(q.fields_desc):
if isinstance(f, PacketListField):
for r in getattr(q, f.name):
fuzz(r, _inplace=1)
Expand Down
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